EP0100621A2 - Vereisungsfühler und Verfahren zur Entdeckung von Eisbildung - Google Patents

Vereisungsfühler und Verfahren zur Entdeckung von Eisbildung Download PDF

Info

Publication number
EP0100621A2
EP0100621A2 EP83304106A EP83304106A EP0100621A2 EP 0100621 A2 EP0100621 A2 EP 0100621A2 EP 83304106 A EP83304106 A EP 83304106A EP 83304106 A EP83304106 A EP 83304106A EP 0100621 A2 EP0100621 A2 EP 0100621A2
Authority
EP
European Patent Office
Prior art keywords
sheet
ice
waves
transducer
ultrasonic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP83304106A
Other languages
English (en)
French (fr)
Other versions
EP0100621A3 (en
EP0100621B1 (de
Inventor
Roger David Watkins
Arthur Blackley Gillespie
Michael Oliver Deighton
Roger Barrie Pike
Colin Basil Scott-Kestin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
UK Atomic Energy Authority
Original Assignee
UK Atomic Energy Authority
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by UK Atomic Energy Authority filed Critical UK Atomic Energy Authority
Publication of EP0100621A2 publication Critical patent/EP0100621A2/de
Publication of EP0100621A3 publication Critical patent/EP0100621A3/en
Application granted granted Critical
Publication of EP0100621B1 publication Critical patent/EP0100621B1/de
Expired legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/11—Analysing solids by measuring attenuation of acoustic waves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D15/00—De-icing or preventing icing on exterior surfaces of aircraft
    • B64D15/20—Means for detecting icing or initiating de-icing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/023—Solids
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/025—Change of phase or condition
    • G01N2291/0251—Solidification, icing, curing composites, polymerisation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/042—Wave modes
    • G01N2291/0422—Shear waves, transverse waves, horizontally polarised waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/042—Wave modes
    • G01N2291/0427—Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S367/00—Communications, electrical: acoustic wave systems and devices
    • Y10S367/908—Material level detection, e.g. liquid level

Definitions

  • This invention relates to instruments for detecting the presence of ice on a surface, in particular on a wing of an aircraft.
  • an aircraft In winter conditions an aircraft may be subjected to rain and snow, and a layer of ice may form on the aircraft's wings. Such an ice layer can be hazardous to safe operation of the aircraft, causing the aircraft to crash on take-off for example.
  • a method for detecting ice on a surface of a thin solid sheet comprising, energising a transducer to cause propagation through a portion of the sheet of ultrasonic waves having their predominant component parallel to the surface of the sheet, detecting the waves by means of a second transducer, measuring the amplitude of the waves received by the second transducer, and detecting by means of the amplitude of the waves received by the second transducer the presence of a layer of ice on the surface of the portion of the sheet.
  • the amplitude and intensity of the waves detected by the second transducer will decrease, as waves having their predominant component parallel to the surface will dissipate energy into the ice layer but will not dissipate energy into air or a liquid layer.
  • an ice detector to detect ice on a surface of a thin solid sheet, comprising an ultrasonic transducer adapted to cause propagation through a portion of the sheet of ultrasonic waves having their predominant component parallel to the surface of the sheet, an ultrasonic transducer adapted to receive the waves and create a signal representative of the amplitude thereof, and means responsive to the signal to detect the presence of an ice layer on the surface of the portion of the sheet.
  • the waves may be horizontally polarized guided shear waves; or the waves may be a mode of Lamb wave whose predominant component is horizontal.
  • horizontal means parallel to the surface, while vertical means normal to the surface.
  • the transducers may be attached to the opposite surface of the portion of the sheet to that on which an ice layer may develop, and may be generated and received by piezoelectric or electromagnetic means.
  • an ice detector comprises a first transducer 10 attached to one surface 12 of a metal sheet 14, opposite the surface 16 on which icing is expected to occur.
  • the transducer 10 is connected by a coaxial cable 20 to a signal generator 22, which when energised causes the transducer 10 to oscillate at a frequency such as to cause pulses of horizontally polarized shear waves to propagate through the sheet 14 with a wavelength comparable with the thickness of the sheet 14, so that the shear waves are guided by the surfaces 12 and 16.
  • a second transducer 30 identical to the first transducer 10 is attached to the surface 12 of the sheet 14 at a distance from the transducer 10.
  • the second transducer 30 is connected by a coaxial cable 32 to a signal receiver and discriminator 34 for determining whether or not an ice layer exists on the surface 16 from a measurement of the amplitude of the signals from the second transducer' 30.
  • the transducer 10 comprises six transducer strips 40 parallel to each other extending perpendicular to the plane of the Figure and spaced apart at a distance equal to the wavelength of the ultrasonic shear waves in the sheet 14, held in a solid matrix 42.
  • Each strip 40 is of length 30mm and is bonded to the surface 12 by an electrically conducting layer 44.
  • Each strip 40 is made of a piezo electric material and has contacts on opposing top and bottom surfaces (not shown) by means of which it can be excited into vibrations parallel to its length. These vibrations are in phase with the other strips 40, and cause horizontally polarised shear waves to propagate in the sheet 14.
  • the transducer 30 is of identical construction to the transducer 10.
  • a shear wave propagating in the sheet 14 drives each of the strips 40 of the transducer 30 into vibrations parallel to its length, thereby inducing a voltage between the contacts on the top and bottom surfaces of the strips 40 of the transducer 30.
  • the signal generator 22 is energised to produce a chopped continuous wave, the number of cycles in each burst being approximately equal to the number of transducer strips 40 in each of the transducers 10 and 30, so that the first transducer 10 causes pulses of horizontally polarised ultrasonic shear waves to propagate through the sheet 14.
  • the pulses are received by the second transducer 30 which sends a signal, representative of the amplitude of the pulses, to the signal receiver and discriminator 34.
  • the signal receiver and discriminator 34 responds only to a signal corresponding to a pulse which has travelled directly from the first transducer 10 to the second transducer 30, the signal receiver and discriminator 34 is gated to operate within a time interval about 5% on either side of the expected time of arrival of the pulse. If the surface 16 is dry, or covered in water (in which horizontally polarised shear waves cannot propagate) the pulses will have a larger amplitude than if the surface 16 is covered by a layer of ice, in which shear waves can propagate. This is because some of the energy of the shear wave pulse in the sheet 14 will be dissipated in causing waves to propagate through the ice. Thus the ice detector can detect ice adhering to the surface 16 but is insensitive to the presence of water.
  • the frequency of the continuous wave produced by the signal generator 22 depends on the mode of wave which it is desired to propagate through the sheet 14. For example, for a zero-order symmetrical horizontally polarised shear wave a frequency in the range 250 kHz to 1 MHz may be used. The pulse repetition frequency is limited by reverberation of the pulses, but may conveniently be 50 Hz. The distance between the first transducer 10 and the second transducer 30 along the sheet 14 might be as large.as 5 or 10 metres, although this depends on the material of which the sheet 14 is made, and on the sensitivity of the signal receiver and discriminator 34.
  • the sensitivity of the ice detector to different thicknesses of ice depends upon the frequency (and hence the wavelength) of the ultrasonic waves. It has been found that an ice detector generating zero-order symmetrical horizontally polarised shear waves and operating at 1 MHz is sensitive to an ice layer about half as thick as that to which a similar ice detector operating at 500 kHz is sensitive. The frequency of operation of the ice detector can therefore be chosen to provide a required sensitivity.
  • an electromagnetic transducer 50 which may be used in place of the transducers 10 and 30 on a metal sheet 14.
  • the electromagnetic transducer 50 comprises six strips 52 of soft ferromagnetic material extending parallel to each other and perpendicular to the plane of the Figure, of length 30mm, and spaced apart at a distance equal to the wavelength of the ultrasonic shear waves in the sheet 14 by spacers 56 of non-ferromagnetic material.
  • Two ceramic magnets 58, one on each side of the sheet 14, produce a magnetic field perpendicular to the surface of the sheet 14 which is strongest adjacent to the ferromagnetic strips 52.
  • a coil 60 of ten turns of wire is wound around the ferromagnetic strips 52 and the spacers 56, a part of each turn lying adjacent to one surface 12 of the sheet 14 and parallel to the plane of the Figure.
  • the ferromagnetic strips 52 and the coil 60 are located adjacent to the surface 12 of the sheet 14 but are not bonded to it.
  • An alternating current (from a source which is not shown in the Figure) flowing in the coil 60 induces eddy currents in the surface 12 of the sheet 14 parallel to the plane of the Figure, so that the portions of the surface 12 adjacent to the ferromagnetic strips 52 experience forces perpendicular to the plane of the Figure, and so shear waves are caused to propagate in the sheet 14. Similarly, a shear wave propagating in the sheet 14 adjacent to the ferromagnetic strips 52 will induce an alternating electromotive force in the coil 60.
  • An ice detector utilizing two transducers 50 in place of the transducers 10 and 30 operates in the same manner as that described above in relation to the ice detector of Figures 1 and 2.
  • transducers 10, 30 and 50 have been described as comprising six strips 40 or 52, a different number of strips may be found more convenient. Each transducer may have as few as one strip, but for adequate selectivity of ultrasonic wave mode a number greater than five is preferable.
  • each strip 40 or 52 determines the directivity of the transducer 10, 30 or 50, but that the length may also be dictated by installation constraints.
  • the strips are of length thirty millimetres, but, for example, strips of length between 10mm and 50mm may be convenient.
  • the width of the strips is preferably equal to about a fifth of the wavelength of the ultrasonic waves generated, but the strips may be of any convenient width less than about half the wavelength.
  • the ultrasonic waves will be guided by the surfaces of the sheet, and the transducers 10, 30 or 50 may be situated on either side of the sheet.
  • the thickness of the ice layer may if desired be measured by a conventional thickness gauge monitor (not shown) attached to the sheet 14 at a position between the first and the second transducers of the ice detector.

Landscapes

  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Biochemistry (AREA)
  • Acoustics & Sound (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
EP83304106A 1982-08-03 1983-07-15 Vereisungsfühler und Verfahren zur Entdeckung von Eisbildung Expired EP0100621B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB8222419 1982-08-03
GB8222419 1982-08-03
GB8235668 1982-12-16
GB8235668 1982-12-16

Publications (3)

Publication Number Publication Date
EP0100621A2 true EP0100621A2 (de) 1984-02-15
EP0100621A3 EP0100621A3 (en) 1986-03-12
EP0100621B1 EP0100621B1 (de) 1988-09-07

Family

ID=26283504

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83304106A Expired EP0100621B1 (de) 1982-08-03 1983-07-15 Vereisungsfühler und Verfahren zur Entdeckung von Eisbildung

Country Status (5)

Country Link
US (1) US4604612A (de)
EP (1) EP0100621B1 (de)
CA (1) CA1214255A (de)
DE (1) DE3377911D1 (de)
GB (1) GB2124764B (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0393960A1 (de) * 1989-04-20 1990-10-24 Simmonds Precision Products Inc. Einrichtung zum Feststellen der Vereisung und Verfahren
FR2695373A1 (fr) * 1992-09-08 1994-03-11 Soundek Oy Détecteur pour indiquer une formation de glace sur l'aile d'un aéronef.
WO1995015883A1 (en) * 1992-10-15 1995-06-15 Jouko Halme Method for installing the sensor wire of an ice detector in an aircraft
WO1996018894A1 (en) * 1994-12-13 1996-06-20 The B.F. Goodrich Company Contaminant detection system
EP1644905A2 (de) * 2003-07-01 2006-04-12 Texzec, Inc. Schallwellen-eis- und wasserdetektor

Families Citing this family (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4553137A (en) * 1983-06-01 1985-11-12 Rosemount Inc. Non-intrusive ice detector
US5134380A (en) * 1986-02-10 1992-07-28 Otakar Jonas Icing detector and method
DE3634374A1 (de) * 1986-10-09 1988-04-21 Fraunhofer Ges Forschung Verfahren und vorrichtung zum bestimmen der dicke eines bandfoermigen oder plattenfoermigen werkstueckes
FR2605402B1 (fr) * 1986-10-15 1991-07-26 Onera (Off Nat Aerospatiale) Dispositif de la detection de la presence de givre et/ou de mesure de l'epaisseur de givre par ultra-sons et sonde de givrage utilisable dans un tel dispositif
US5189914A (en) * 1988-02-29 1993-03-02 The Regents Of The University Of California Plate-mode ultrasonic sensor
US5398547A (en) * 1989-01-10 1995-03-21 Innovative Dynamics, Inc. Apparatus for measuring ice distribution profiles
US5206806A (en) * 1989-01-10 1993-04-27 Gerardi Joseph J Smart skin ice detection and de-icing system
US5195046A (en) * 1989-01-10 1993-03-16 Gerardi Joseph J Method and apparatus for structural integrity monitoring
GB8905822D0 (en) * 1989-03-14 1989-04-26 Sensotect Limited A stress wave load cell
DE4033975A1 (de) * 1989-10-26 1991-05-08 Aisin Seiki Regentropfensensor
US5117687A (en) * 1990-01-11 1992-06-02 Gerardi Joseph J Omnidirectional aerodynamic sensor
US5051645A (en) * 1990-01-30 1991-09-24 Johnson Service Company Acoustic wave H2 O phase-change sensor capable of self-cleaning and distinguishing air, water, dew, frost and ice
US5187980A (en) * 1990-05-31 1993-02-23 The United States Of America As Represented By The United States Department Of Energy Method and apparatus for acoustic plate mode liquid-solid phase transition detection
FR2703786B1 (fr) * 1993-04-07 1995-06-23 Intertechnique Sa Procede et dispositif a ultrasons de detection et d'identification de contaminant tel que le givre a la surface d'une structure.
FI95751C (fi) * 1993-12-09 1996-03-11 Labko Ab Oy Menetelmä veden eri faasien tunnistamiseksi ja menetelmässä käytettäväanturijärjestely
US5557261A (en) * 1994-05-06 1996-09-17 Nichols Research Corporation Ice monitoring and detection system
US5497100A (en) * 1994-10-17 1996-03-05 Hughes Aircraft Company Surface condition sensing system
US5743161A (en) * 1995-07-31 1998-04-28 Boudreau; Jon P. Angularly adjustable table saw jig
US6052056A (en) * 1996-04-26 2000-04-18 Icg Technologies, Llc Substance detection system and method
US5922958A (en) * 1996-05-22 1999-07-13 Rosemount Aerospace Inc. Acoustic channel for contaminant detection on a surface
JPH10227768A (ja) * 1997-02-13 1998-08-25 Aisin Seiki Co Ltd 雨滴検出装置
US5900736A (en) * 1997-07-28 1999-05-04 Transtech Systems, Inc. Paving material density indicator and method using capacitance
US6286370B1 (en) * 1999-02-03 2001-09-11 Naveen Neil Sinha Method using ultrasound for detecting materials on metal surfaces
US6414497B1 (en) 2000-05-04 2002-07-02 Transtech Systems, Inc. Paving material analyzer system and method
US6803771B2 (en) 2000-05-04 2004-10-12 Transtech Systems, Inc. Paving material analyzer system and method
US6731225B2 (en) 2002-02-14 2004-05-04 Lockheed Martin Corporation Method and apparatus for detecting and measuring thickness of ice on aircraft
US6963205B2 (en) 2002-08-21 2005-11-08 Lundstrom John W Electrically measuring soil dry density
FR2860293B1 (fr) * 2003-09-26 2006-01-20 Airbus France Dispositif et procede pour mesure de parametres en essai de vol d'un aeronef
US7697375B2 (en) * 2004-03-17 2010-04-13 Baker Hughes Incorporated Combined electro-magnetic acoustic transducer
US7104502B2 (en) 2004-03-31 2006-09-12 Rosemount Aerospace Inc. Ice detector for improved ice detection at near freezing condition
US7219024B2 (en) 2004-05-26 2007-05-15 Transtech Systems, Inc. Material analysis including density and moisture content determinations
JP4568377B1 (ja) * 2010-04-27 2010-10-27 株式会社Ｉｈｉ検査計測 Ｌモードガイド波センサとその使用方法
US9327839B2 (en) 2011-08-05 2016-05-03 General Atomics Method and apparatus for inhibiting formation of and/or removing ice from aircraft components
US9359081B2 (en) 2012-06-12 2016-06-07 The Boeing Company Icing condition detection system
US10099791B2 (en) 2015-07-28 2018-10-16 Fbs, Inc. Magnetostrictive multi-frequency guided wave ice sensing probe
US10466206B2 (en) * 2016-12-12 2019-11-05 Southwest Research Institute Non destructive magnetostrictive testing with unidirectional guided waves generated by ferromagnetic strip sensor
US11549914B2 (en) 2020-12-21 2023-01-10 Hamilton Sundstrand Corporation Surface acoustic wave sensors for air data probes
CN113405631B (zh) * 2021-05-19 2022-08-12 哈尔滨工程大学 一种用于冰下水深测量的换能器与冰面耦合装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB564513A (en) * 1943-01-26 1944-10-02 Tecalemit Ltd Apparatus for detecting and indicating and (or) measuring ice formation on vehicles
FR1482385A (fr) * 1966-06-06 1967-05-26 Glass Developments Ltd Détecteur de givre
FR2054642A1 (de) * 1969-07-18 1971-04-23 Rotax Ltd
FR2346218A1 (fr) * 1976-04-01 1977-10-28 System Dev Corp Detecteur de givre a micro-ondes
GB2060883A (en) * 1979-10-10 1981-05-07 Vaisala Oy Apparatus for detecting freezing of the surface of an asphalt road or the like
GB2070772A (en) * 1980-02-29 1981-09-09 Vaisala Oy Method and apparatus for detection of dew point

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2956184A (en) * 1954-11-01 1960-10-11 Honeywell Regulator Co Transducer
US3240054A (en) * 1962-12-24 1966-03-15 Gabb Special Products Inc Ice detector
GB1117664A (en) * 1965-06-08 1968-06-19 Glass Developments Ltd Improvements in or relating to acoustically operated ice detectors
US3409869A (en) * 1965-07-21 1968-11-05 Navy Usa Deep submergence acoustic transducer array construction
US3512400A (en) * 1967-04-13 1970-05-19 Panametrics Ultrasonic testing method
US3612924A (en) * 1969-09-26 1971-10-12 Continental Can Co Mass loaded magnetostrictive transducer
SE361950B (de) * 1970-07-16 1973-11-19 Helge Meuller Ab
US3706981A (en) * 1971-02-08 1972-12-19 Atlee S Hart Indicating system for detecting gaseous and non-gaseous states
US3854060A (en) * 1973-10-12 1974-12-10 Us Navy Transducer for fm sonar application
US4376302A (en) * 1978-04-13 1983-03-08 The United States Of America As Represented By The Secretary Of The Navy Piezoelectric polymer hydrophone
FR2454593A1 (fr) * 1979-04-20 1980-11-14 York Sa Froid Indl Appareil haute pression de production de neige artificielle avec reglage du melange air/eau en fonction de la temperature humide de l'air ambiant
FR2454675A1 (fr) * 1979-04-20 1980-11-14 Framatome Sa Procede de controle de crayons combustibles destines a des assemblages pour reacteur nucleaire et dispositif correspondant
US4253337A (en) * 1979-08-08 1981-03-03 Rockwell International Corporation Ultrasonic nondestructive testing method
JPS5712329A (en) * 1980-06-25 1982-01-22 Hitachi Ltd Frost sensor
US4461178A (en) * 1982-04-02 1984-07-24 The Charles Stark Draper Laboratory, Inc. Ultrasonic aircraft ice detector using flexural waves

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB564513A (en) * 1943-01-26 1944-10-02 Tecalemit Ltd Apparatus for detecting and indicating and (or) measuring ice formation on vehicles
FR1482385A (fr) * 1966-06-06 1967-05-26 Glass Developments Ltd Détecteur de givre
FR2054642A1 (de) * 1969-07-18 1971-04-23 Rotax Ltd
FR2346218A1 (fr) * 1976-04-01 1977-10-28 System Dev Corp Detecteur de givre a micro-ondes
GB2060883A (en) * 1979-10-10 1981-05-07 Vaisala Oy Apparatus for detecting freezing of the surface of an asphalt road or the like
GB2070772A (en) * 1980-02-29 1981-09-09 Vaisala Oy Method and apparatus for detection of dew point

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0393960A1 (de) * 1989-04-20 1990-10-24 Simmonds Precision Products Inc. Einrichtung zum Feststellen der Vereisung und Verfahren
FR2695373A1 (fr) * 1992-09-08 1994-03-11 Soundek Oy Détecteur pour indiquer une formation de glace sur l'aile d'un aéronef.
US5467944A (en) * 1992-09-08 1995-11-21 Soundek Oy Detector for indicating ice formation on the wing of an aircraft
WO1995015883A1 (en) * 1992-10-15 1995-06-15 Jouko Halme Method for installing the sensor wire of an ice detector in an aircraft
WO1996018894A1 (en) * 1994-12-13 1996-06-20 The B.F. Goodrich Company Contaminant detection system
EP1644905A2 (de) * 2003-07-01 2006-04-12 Texzec, Inc. Schallwellen-eis- und wasserdetektor
EP1644905A4 (de) * 2003-07-01 2011-10-26 Illinois Tool Works Schallwellen-eis- und wasserdetektor

Also Published As

Publication number Publication date
GB2124764B (en) 1986-01-08
GB8318822D0 (en) 1983-08-10
US4604612A (en) 1986-08-05
CA1214255A (en) 1986-11-18
EP0100621A3 (en) 1986-03-12
EP0100621B1 (de) 1988-09-07
DE3377911D1 (en) 1988-10-13
GB2124764A (en) 1984-02-22

Similar Documents

Publication Publication Date Title
US4604612A (en) Ice detector
US5619423A (en) System, method and apparatus for the ultrasonic inspection of liquid filled tubulars and vessels
FI61249B (fi) Anordning foer indikering av nedisning av asfaltsvaeg eller motsvarande
US4127035A (en) Electromagnetic transducer
US4678993A (en) Distance measuring device operating with torsional ultrasonic waves detected without mode conversion
US2787160A (en) Ultrasonic liquid depth indicator
US5467944A (en) Detector for indicating ice formation on the wing of an aircraft
US5966983A (en) Assembly for sensing and/or monitoring a predetermined level in a vessel
US4523473A (en) Magneto-elastic material defect detector
US6924642B1 (en) Magnetorestrictive transducer for generating and measuring elastic waves, and apparatus for structural diagnosis using the same
US4216352A (en) Two coordinate position sensing systems
US4765750A (en) Method of determining subsurface property value gradient
JPH0339589B2 (de)
JP4465420B2 (ja) 磁歪超音波素子及びこれを利用した非破壊検査方法
US5714689A (en) Zig zag electromagnetic acoustic transducer scan
CA2097583C (en) Hydrogen damage confirmation with emats
JPH02291933A (ja) 応力波ロードセル
JPH0875714A (ja) 探傷試験方法及び探触子
JP2538596B2 (ja) 電磁超音波トランスジュ−サ
JPH04310858A (ja) ケーブル欠陥部の超音波検出・位置探知方法及び装置
JPH07286916A (ja) 残留応力測定方法
JPS56157861A (en) Measuring system for velocity of flow of fluid
KR100308828B1 (ko) 실시간랑크폴드값측정용자왜형전자기초음파측정장치
Jia et al. Experimental investigations of Lamb waves on pulsed piezoelectric transducers and their ultrasonic radiation into liquids
SU868561A1 (ru) Способ дефектоскопии ферромагнитных изделий

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE FR IT NL SE

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR IT NL SE

17P Request for examination filed

Effective date: 19860214

17Q First examination report despatched

Effective date: 19870108

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR IT NL SE

ITF It: translation for a ep patent filed

Owner name: JACOBACCI & PERANI S.P.A.

REF Corresponds to:

Ref document number: 3377911

Country of ref document: DE

Date of ref document: 19881013

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19890716

ITTA It: last paid annual fee
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19890731

Year of fee payment: 7

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19900702

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19900706

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19910201

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19920331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19920401

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

EUG Se: european patent has lapsed

Ref document number: 83304106.4

Effective date: 19900418